If you would like another opinion of the new programs, take a look at Randy Seaver's post entitled, "First Look at the FamilySearch Family Tree Mobile App."
Here are some screenshots with comments:
This is the sign in screen for the Tree app. You use your FamilySearch account login and password.
The app seems to come up in Photo view. I didn't see any other way to view the Family Tree.
The Settings menu was rather scanty and simple. I assume other preferences will be added in subsequent versions.
This is an example of a Details Page. It looks like other views are available through menu items. Probably a good choice of features.
You can switch to put the current person in the No. 1 position, but the app is limited to this particular view, as I mentioned above.
It took a couple of minute load all of my photos. You could add a photo and otherwise the app was much more limited than the desktop program.
You can view a single file in the Photos Section, but nothing more.
I expect both programs will change over time. Right now they are interesting and the programs seem to be poised to supply more features.